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to crystallisation as before. The sodium naphthalene sulphonatc
is separated by filtration, and dried in a basin on the water-bath.
The mother-liquor, on evaporation, yields a further quantity of
the salt. Yield, about 60 grains.
1. (',,,11,+ ILSO.,-CtoH7S< UI + TU).
2. 2C:IOI I7S( >.,! I + CaO - (C10I l7SO,),Ca+ 1LO.
rwpcrtics.......Koliated crystals; soluble in water. See
ppendix, p. 315.
1'RKPA RATION IO6.
Kllcr, Atiim/fti, 1869, 152, 275 ; K. l«'ischcr, Anlcitung s. d.
30 ijnns. /^-naphthalene sulphonatc of sodium.
90 „ i'austic sod:i,
The caustic soda and water arc; heated in a nickel fir silver
crucible, and stirred with a thermometer, protected as described W
under the preparation of phenol (p. 179). When the temperature V-
reaches 2So', the powdered naphthalene sulphonate is added a JM'.I
little at a time. When all has been added, the temperature is '.^t
raised. At about 300" the mas-s froths up and becomes li^'ht
yellow in colour, which indicates the commencement of the r»!
reaction. The temperature is maintained at. 3io°-~32o': for a s * '
few minutes, and the end of the process is indicated by the ' i L
yellow mass becoming thinner and also darker in colour, and *i
separating into two layers. The stirring is now stopped and ff
the (lame withdrawn. The product, when cold, is dissolved in t l j'|J
H little water, rind acidified with a, mixture of equal volumes of ' |
concentrated hydrochloric acid and water.* tf;
The naphthol is filtered, off when cold, and is recrystalliscd l|
from water. Meld, 15 grains. i tf
Cj0ll7S< )3Na -H NaOH - C10I I7(JNa, + Na I ISO.,. ^
Colourless leaflets ; m. p. i22r; ; b. p. 286'. ^